[mirror_ubuntu-bionic-kernel.git] / fs / pstore / inode.c

/*
 * Persistent Storage - ramfs parts.
 *
 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/fsnotify.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/string.h>
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/ramfs.h>
#include <linux/parser.h>
#include <linux/sched.h>
#include <linux/magic.h>
#include <linux/pstore.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>

#include "internal.h"

#define	PSTORE_NAMELEN	64

static DEFINE_SPINLOCK(allpstore_lock);
static LIST_HEAD(allpstore);

struct pstore_private {
	struct list_head list;
	struct pstore_record *record;
	size_t total_size;
};

struct pstore_ftrace_seq_data {
	const void *ptr;
	size_t off;
	size_t size;
};

#define REC_SIZE sizeof(struct pstore_ftrace_record)

static void free_pstore_private(struct pstore_private *private)
{
	if (!private)
		return;
	if (private->record) {
		kfree(private->record->buf);
		kfree(private->record);
	}
	kfree(private);
}

static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
{
	struct pstore_private *ps = s->private;
	struct pstore_ftrace_seq_data *data;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
		return NULL;

	data->off = ps->total_size % REC_SIZE;
	data->off += *pos * REC_SIZE;
	if (data->off + REC_SIZE > ps->total_size) {
		kfree(data);
		return NULL;
	}

	return data;

}

static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
{
	kfree(v);
}

static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
	struct pstore_private *ps = s->private;
	struct pstore_ftrace_seq_data *data = v;

	data->off += REC_SIZE;
	if (data->off + REC_SIZE > ps->total_size)
		return NULL;

	(*pos)++;
	return data;
}

static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
{
	struct pstore_private *ps = s->private;
	struct pstore_ftrace_seq_data *data = v;
	struct pstore_ftrace_record *rec;

	rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);

	seq_printf(s, "CPU:%d ts:%llu %08lx  %08lx  %pf <- %pF\n",
		   pstore_ftrace_decode_cpu(rec),
		   pstore_ftrace_read_timestamp(rec),
		   rec->ip, rec->parent_ip, (void *)rec->ip,
		   (void *)rec->parent_ip);

	return 0;
}

static const struct seq_operations pstore_ftrace_seq_ops = {
	.start	= pstore_ftrace_seq_start,
	.next	= pstore_ftrace_seq_next,
	.stop	= pstore_ftrace_seq_stop,
	.show	= pstore_ftrace_seq_show,
};

static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
						size_t count, loff_t *ppos)
{
	struct seq_file *sf = file->private_data;
	struct pstore_private *ps = sf->private;

	if (ps->record->type == PSTORE_TYPE_FTRACE)
		return seq_read(file, userbuf, count, ppos);
	return simple_read_from_buffer(userbuf, count, ppos,
				       ps->record->buf, ps->total_size);
}

static int pstore_file_open(struct inode *inode, struct file *file)
{
	struct pstore_private *ps = inode->i_private;
	struct seq_file *sf;
	int err;
	const struct seq_operations *sops = NULL;

	if (ps->record->type == PSTORE_TYPE_FTRACE)
		sops = &pstore_ftrace_seq_ops;

	err = seq_open(file, sops);
	if (err < 0)
		return err;

	sf = file->private_data;
	sf->private = ps;

	return 0;
}

static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
{
	struct seq_file *sf = file->private_data;

	if (sf->op)
		return seq_lseek(file, off, whence);
	return default_llseek(file, off, whence);
}

static const struct file_operations pstore_file_operations = {
	.open		= pstore_file_open,
	.read		= pstore_file_read,
	.llseek		= pstore_file_llseek,
	.release	= seq_release,
};

/*
 * When a file is unlinked from our file system we call the
 * platform driver to erase the record from persistent store.
 */
static int pstore_unlink(struct inode *dir, struct dentry *dentry)
{
	struct pstore_private *p = d_inode(dentry)->i_private;
	struct pstore_record *record = p->record;

	if (!record->psi->erase)
		return -EPERM;

	mutex_lock(&record->psi->read_mutex);
	record->psi->erase(record);
	mutex_unlock(&record->psi->read_mutex);

	return simple_unlink(dir, dentry);
}

static void pstore_evict_inode(struct inode *inode)
{
	struct pstore_private	*p = inode->i_private;
	unsigned long		flags;

	clear_inode(inode);
	if (p) {
		spin_lock_irqsave(&allpstore_lock, flags);
		list_del(&p->list);
		spin_unlock_irqrestore(&allpstore_lock, flags);
		free_pstore_private(p);
	}
}

static const struct inode_operations pstore_dir_inode_operations = {
	.lookup		= simple_lookup,
	.unlink		= pstore_unlink,
};

static struct inode *pstore_get_inode(struct super_block *sb)
{
	struct inode *inode = new_inode(sb);
	if (inode) {
		inode->i_ino = get_next_ino();
		inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
	}
	return inode;
}

enum {
	Opt_kmsg_bytes, Opt_err
};

static const match_table_t tokens = {
	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
	{Opt_err, NULL}
};

static void parse_options(char *options)
{
	char		*p;
	substring_t	args[MAX_OPT_ARGS];
	int		option;

	if (!options)
		return;

	while ((p = strsep(&options, ",")) != NULL) {
		int token;

		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_kmsg_bytes:
			if (!match_int(&args[0], &option))
				pstore_set_kmsg_bytes(option);
			break;
		}
	}
}

/*
 * Display the mount options in /proc/mounts.
 */
static int pstore_show_options(struct seq_file *m, struct dentry *root)
{
	if (kmsg_bytes != PSTORE_DEFAULT_KMSG_BYTES)
		seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes);
	return 0;
}

static int pstore_remount(struct super_block *sb, int *flags, char *data)
{
	sync_filesystem(sb);
	parse_options(data);

	return 0;
}

static const struct super_operations pstore_ops = {
	.statfs		= simple_statfs,
	.drop_inode	= generic_delete_inode,
	.evict_inode	= pstore_evict_inode,
	.remount_fs	= pstore_remount,
	.show_options	= pstore_show_options,
};

static struct super_block *pstore_sb;

bool pstore_is_mounted(void)
{
	return pstore_sb != NULL;
}

/*
 * Make a regular file in the root directory of our file system.
 * Load it up with "size" bytes of data from "buf".
 * Set the mtime & ctime to the date that this record was originally stored.
 */
int pstore_mkfile(struct dentry *root, struct pstore_record *record)
{
	struct dentry		*dentry;
	struct inode		*inode;
	int			rc = 0;
	char			name[PSTORE_NAMELEN];
	struct pstore_private	*private, *pos;
	unsigned long		flags;
	size_t			size = record->size + record->ecc_notice_size;

	WARN_ON(!inode_is_locked(d_inode(root)));

	spin_lock_irqsave(&allpstore_lock, flags);
	list_for_each_entry(pos, &allpstore, list) {
		if (pos->record->type == record->type &&
		    pos->record->id == record->id &&
		    pos->record->psi == record->psi) {
			rc = -EEXIST;
			break;
		}
	}
	spin_unlock_irqrestore(&allpstore_lock, flags);
	if (rc)
		return rc;

	rc = -ENOMEM;
	inode = pstore_get_inode(root->d_sb);
	if (!inode)
		goto fail;
	inode->i_mode = S_IFREG | 0444;
	inode->i_fop = &pstore_file_operations;
	private = kzalloc(sizeof(*private), GFP_KERNEL);
	if (!private)
		goto fail_alloc;
	private->record = record;

	switch (record->type) {
	case PSTORE_TYPE_DMESG:
		scnprintf(name, sizeof(name), "dmesg-%s-%llu%s",
			  record->psi->name, record->id,
			  record->compressed ? ".enc.z" : "");
		break;
	case PSTORE_TYPE_CONSOLE:
		scnprintf(name, sizeof(name), "console-%s-%llu",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_FTRACE:
		scnprintf(name, sizeof(name), "ftrace-%s-%llu",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_MCE:
		scnprintf(name, sizeof(name), "mce-%s-%llu",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_PPC_RTAS:
		scnprintf(name, sizeof(name), "rtas-%s-%llu",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_PPC_OF:
		scnprintf(name, sizeof(name), "powerpc-ofw-%s-%llu",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_PPC_COMMON:
		scnprintf(name, sizeof(name), "powerpc-common-%s-%llu",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_PMSG:
		scnprintf(name, sizeof(name), "pmsg-%s-%llu",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_PPC_OPAL:
		scnprintf(name, sizeof(name), "powerpc-opal-%s-%llu",
			  record->psi->name, record->id);
		break;
	case PSTORE_TYPE_UNKNOWN:
		scnprintf(name, sizeof(name), "unknown-%s-%llu",
			  record->psi->name, record->id);
		break;
	default:
		scnprintf(name, sizeof(name), "type%d-%s-%llu",
			  record->type, record->psi->name, record->id);
		break;
	}

	dentry = d_alloc_name(root, name);
	if (!dentry)
		goto fail_private;

	inode->i_size = private->total_size = size;

	inode->i_private = private;

	if (record->time.tv_sec)
		inode->i_mtime = inode->i_ctime = record->time;

	d_add(dentry, inode);

	spin_lock_irqsave(&allpstore_lock, flags);
	list_add(&private->list, &allpstore);
	spin_unlock_irqrestore(&allpstore_lock, flags);

	return 0;

fail_private:
	free_pstore_private(private);
fail_alloc:
	iput(inode);

fail:
	return rc;
}

/*
 * Read all the records from the persistent store. Create
 * files in our filesystem.  Don't warn about -EEXIST errors
 * when we are re-scanning the backing store looking to add new
 * error records.
 */
void pstore_get_records(int quiet)
{
	struct pstore_info *psi = psinfo;
	struct dentry *root;

	if (!psi || !pstore_sb)
		return;

	root = pstore_sb->s_root;

	inode_lock(d_inode(root));
	pstore_get_backend_records(psi, root, quiet);
	inode_unlock(d_inode(root));
}

static int pstore_fill_super(struct super_block *sb, void *data, int silent)
{
	struct inode *inode;

	pstore_sb = sb;

	sb->s_maxbytes		= MAX_LFS_FILESIZE;
	sb->s_blocksize		= PAGE_SIZE;
	sb->s_blocksize_bits	= PAGE_SHIFT;
	sb->s_magic		= PSTOREFS_MAGIC;
	sb->s_op		= &pstore_ops;
	sb->s_time_gran		= 1;

	parse_options(data);

	inode = pstore_get_inode(sb);
	if (inode) {
		inode->i_mode = S_IFDIR | 0750;
		inode->i_op = &pstore_dir_inode_operations;
		inode->i_fop = &simple_dir_operations;
		inc_nlink(inode);
	}
	sb->s_root = d_make_root(inode);
	if (!sb->s_root)
		return -ENOMEM;

	pstore_get_records(0);

	return 0;
}

static struct dentry *pstore_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data)
{
	return mount_single(fs_type, flags, data, pstore_fill_super);
}

static void pstore_kill_sb(struct super_block *sb)
{
	kill_litter_super(sb);
	pstore_sb = NULL;
}

static struct file_system_type pstore_fs_type = {
	.owner          = THIS_MODULE,
	.name		= "pstore",
	.mount		= pstore_mount,
	.kill_sb	= pstore_kill_sb,
};

static int __init init_pstore_fs(void)
{
	int err;

	/* Create a convenient mount point for people to access pstore */
	err = sysfs_create_mount_point(fs_kobj, "pstore");
	if (err)
		goto out;

	err = register_filesystem(&pstore_fs_type);
	if (err < 0)
		sysfs_remove_mount_point(fs_kobj, "pstore");

out:
	return err;
}
module_init(init_pstore_fs)

static void __exit exit_pstore_fs(void)
{
	unregister_filesystem(&pstore_fs_type);
	sysfs_remove_mount_point(fs_kobj, "pstore");
}
module_exit(exit_pstore_fs)

MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
MODULE_LICENSE("GPL");
Commit	Line	Data
ca01d6dd TL	1	/*
	2	* Persistent Storage - ramfs parts.
	3	*
	4	* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	18	*/
	19
	20	#include <linux/module.h>
	21	#include <linux/fs.h>
	22	#include <linux/fsnotify.h>
	23	#include <linux/pagemap.h>
	24	#include <linux/highmem.h>
	25	#include <linux/time.h>
	26	#include <linux/init.h>
6dda9266	27	#include <linux/list.h>
ca01d6dd TL	28	#include <linux/string.h>
ca01d6dd TL	29	#include <linux/mount.h>
060287b8	30	#include <linux/seq_file.h>
ca01d6dd	31	#include <linux/ramfs.h>
366f7e7a	32	#include <linux/parser.h>
ca01d6dd TL	33	#include <linux/sched.h>
	34	#include <linux/magic.h>
	35	#include <linux/pstore.h>
	36	#include <linux/slab.h>
6dda9266	37	#include <linux/spinlock.h>
ca01d6dd TL	38	#include <linux/uaccess.h>
	39
	40	#include "internal.h"
	41
	42	#define PSTORE_NAMELEN 64
	43
6dda9266 TL	44	static DEFINE_SPINLOCK(allpstore_lock);
	45	static LIST_HEAD(allpstore);
	46
ca01d6dd	47	struct pstore_private {
6dda9266	48	struct list_head list;
83f70f07 KC	49	struct pstore_record *record;
83f70f07 KC	50	size_t total_size;
ca01d6dd TL	51	};
ca01d6dd TL	52
060287b8 AV	53	struct pstore_ftrace_seq_data {
	54	const void *ptr;
	55	size_t off;
	56	size_t size;
	57	};
	58
	59	#define REC_SIZE sizeof(struct pstore_ftrace_record)
	60
1dfff7dd KC	61	static void free_pstore_private(struct pstore_private *private)
	62	{
	63	if (!private)
	64	return;
83f70f07 KC	65	if (private->record) {
	66	kfree(private->record->buf);
	67	kfree(private->record);
	68	}
1dfff7dd KC	69	kfree(private);
	70	}
	71
060287b8 AV	72	static void pstore_ftrace_seq_start(struct seq_file s, loff_t *pos)
	73	{
	74	struct pstore_private *ps = s->private;
	75	struct pstore_ftrace_seq_data *data;
	76
	77	data = kzalloc(sizeof(*data), GFP_KERNEL);
	78	if (!data)
	79	return NULL;
	80
83f70f07	81	data->off = ps->total_size % REC_SIZE;
060287b8	82	data->off += pos REC_SIZE;
83f70f07	83	if (data->off + REC_SIZE > ps->total_size) {
060287b8 AV	84	kfree(data);
	85	return NULL;
	86	}
	87
	88	return data;
	89
	90	}
	91
	92	static void pstore_ftrace_seq_stop(struct seq_file s, void v)
	93	{
	94	kfree(v);
	95	}
	96
	97	static void pstore_ftrace_seq_next(struct seq_file s, void v, loff_t pos)
	98	{
	99	struct pstore_private *ps = s->private;
	100	struct pstore_ftrace_seq_data *data = v;
	101
	102	data->off += REC_SIZE;
83f70f07	103	if (data->off + REC_SIZE > ps->total_size)
060287b8 AV	104	return NULL;
	105
	106	(*pos)++;
	107	return data;
	108	}
	109
	110	static int pstore_ftrace_seq_show(struct seq_file s, void v)
	111	{
	112	struct pstore_private *ps = s->private;
	113	struct pstore_ftrace_seq_data *data = v;
83f70f07 KC	114	struct pstore_ftrace_record *rec;
	115
	116	rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
060287b8	117
fbccdeb8 JF	118	seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n",
	119	pstore_ftrace_decode_cpu(rec),
	120	pstore_ftrace_read_timestamp(rec),
	121	rec->ip, rec->parent_ip, (void *)rec->ip,
	122	(void *)rec->parent_ip);
060287b8 AV	123
	124	return 0;
	125	}
	126
	127	static const struct seq_operations pstore_ftrace_seq_ops = {
	128	.start = pstore_ftrace_seq_start,
	129	.next = pstore_ftrace_seq_next,
	130	.stop = pstore_ftrace_seq_stop,
	131	.show = pstore_ftrace_seq_show,
	132	};
	133
fbe0aa1f TL	134	static ssize_t pstore_file_read(struct file file, char __user userbuf,
	135	size_t count, loff_t *ppos)
	136	{
060287b8 AV	137	struct seq_file *sf = file->private_data;
060287b8 AV	138	struct pstore_private *ps = sf->private;
fbe0aa1f	139
83f70f07	140	if (ps->record->type == PSTORE_TYPE_FTRACE)
060287b8	141	return seq_read(file, userbuf, count, ppos);
83f70f07 KC	142	return simple_read_from_buffer(userbuf, count, ppos,
83f70f07 KC	143	ps->record->buf, ps->total_size);
fbe0aa1f TL	144	}
fbe0aa1f TL	145
060287b8 AV	146	static int pstore_file_open(struct inode inode, struct file file)
	147	{
	148	struct pstore_private *ps = inode->i_private;
	149	struct seq_file *sf;
	150	int err;
	151	const struct seq_operations *sops = NULL;
	152
83f70f07	153	if (ps->record->type == PSTORE_TYPE_FTRACE)
060287b8 AV	154	sops = &pstore_ftrace_seq_ops;
	155
	156	err = seq_open(file, sops);
	157	if (err < 0)
	158	return err;
	159
	160	sf = file->private_data;
	161	sf->private = ps;
	162
	163	return 0;
	164	}
	165
965c8e59	166	static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
060287b8 AV	167	{
	168	struct seq_file *sf = file->private_data;
	169
	170	if (sf->op)
965c8e59 AM	171	return seq_lseek(file, off, whence);
965c8e59 AM	172	return default_llseek(file, off, whence);
060287b8 AV	173	}
060287b8 AV	174
fbe0aa1f	175	static const struct file_operations pstore_file_operations = {
060287b8 AV	176	.open = pstore_file_open,
	177	.read = pstore_file_read,
	178	.llseek = pstore_file_llseek,
	179	.release = seq_release,
fbe0aa1f	180	};
ca01d6dd TL	181
	182	/*
	183	* When a file is unlinked from our file system we call the
	184	* platform driver to erase the record from persistent store.
	185	*/
	186	static int pstore_unlink(struct inode dir, struct dentry dentry)
	187	{
2b0143b5	188	struct pstore_private *p = d_inode(dentry)->i_private;
83f70f07	189	struct pstore_record *record = p->record;
ca01d6dd	190
a61072aa	191	if (!record->psi->erase)
bf288333	192	return -EPERM;
a61072aa KC	193
	194	mutex_lock(&record->psi->read_mutex);
	195	record->psi->erase(record);
	196	mutex_unlock(&record->psi->read_mutex);
ca01d6dd TL	197
	198	return simple_unlink(dir, dentry);
	199	}
	200
a872d510 TL	201	static void pstore_evict_inode(struct inode *inode)
a872d510 TL	202	{
6dda9266 TL	203	struct pstore_private *p = inode->i_private;
	204	unsigned long flags;
	205
dbd5768f	206	clear_inode(inode);
6dda9266 TL	207	if (p) {
	208	spin_lock_irqsave(&allpstore_lock, flags);
	209	list_del(&p->list);
	210	spin_unlock_irqrestore(&allpstore_lock, flags);
1dfff7dd	211	free_pstore_private(p);
6dda9266	212	}
a872d510 TL	213	}
a872d510 TL	214
ca01d6dd TL	215	static const struct inode_operations pstore_dir_inode_operations = {
	216	.lookup = simple_lookup,
	217	.unlink = pstore_unlink,
	218	};
	219
22a71c30	220	static struct inode pstore_get_inode(struct super_block sb)
fbe0aa1f TL	221	{
fbe0aa1f TL	222	struct inode *inode = new_inode(sb);
fbe0aa1f TL	223	if (inode) {
fbe0aa1f TL	224	inode->i_ino = get_next_ino();
078cd827	225	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
fbe0aa1f TL	226	}
	227	return inode;
	228	}
	229
366f7e7a TL	230	enum {
	231	Opt_kmsg_bytes, Opt_err
	232	};
	233
	234	static const match_table_t tokens = {
	235	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
	236	{Opt_err, NULL}
	237	};
	238
	239	static void parse_options(char *options)
	240	{
	241	char *p;
	242	substring_t args[MAX_OPT_ARGS];
	243	int option;
	244
	245	if (!options)
	246	return;
	247
	248	while ((p = strsep(&options, ",")) != NULL) {
	249	int token;
	250
	251	if (!*p)
	252	continue;
	253
	254	token = match_token(p, tokens, args);
	255	switch (token) {
	256	case Opt_kmsg_bytes:
	257	if (!match_int(&args[0], &option))
	258	pstore_set_kmsg_bytes(option);
	259	break;
	260	}
	261	}
	262	}
	263
349d7438 DH	264	/*
	265	* Display the mount options in /proc/mounts.
	266	*/
	267	static int pstore_show_options(struct seq_file m, struct dentry root)
	268	{
	269	if (kmsg_bytes != PSTORE_DEFAULT_KMSG_BYTES)
	270	seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes);
	271	return 0;
	272	}
	273
366f7e7a TL	274	static int pstore_remount(struct super_block sb, int flags, char *data)
366f7e7a TL	275	{
02b9984d	276	sync_filesystem(sb);
366f7e7a TL	277	parse_options(data);
	278
	279	return 0;
	280	}
	281
ca01d6dd TL	282	static const struct super_operations pstore_ops = {
	283	.statfs = simple_statfs,
	284	.drop_inode = generic_delete_inode,
a872d510	285	.evict_inode = pstore_evict_inode,
366f7e7a	286	.remount_fs = pstore_remount,
349d7438	287	.show_options = pstore_show_options,
ca01d6dd TL	288	};
	289
	290	static struct super_block *pstore_sb;
ca01d6dd	291
7e26e9ff	292	bool pstore_is_mounted(void)
ca01d6dd	293	{
fbe0aa1f	294	return pstore_sb != NULL;
ca01d6dd TL	295	}
	296
	297	/*
	298	* Make a regular file in the root directory of our file system.
	299	* Load it up with "size" bytes of data from "buf".
	300	* Set the mtime & ctime to the date that this record was originally stored.
	301	*/
3a7d2fd1	302	int pstore_mkfile(struct dentry root, struct pstore_record record)
ca01d6dd	303	{
ca01d6dd TL	304	struct dentry *dentry;
ca01d6dd TL	305	struct inode *inode;
6dda9266	306	int rc = 0;
ca01d6dd	307	char name[PSTORE_NAMELEN];
6dda9266 TL	308	struct pstore_private private, pos;
6dda9266 TL	309	unsigned long flags;
1edd1aa3	310	size_t size = record->size + record->ecc_notice_size;
6dda9266	311
3a7d2fd1 KC	312	WARN_ON(!inode_is_locked(d_inode(root)));
3a7d2fd1 KC	313
6dda9266 TL	314	spin_lock_irqsave(&allpstore_lock, flags);
6dda9266 TL	315	list_for_each_entry(pos, &allpstore, list) {
83f70f07 KC	316	if (pos->record->type == record->type &&
	317	pos->record->id == record->id &&
	318	pos->record->psi == record->psi) {
6dda9266 TL	319	rc = -EEXIST;
	320	break;
	321	}
	322	}
	323	spin_unlock_irqrestore(&allpstore_lock, flags);
	324	if (rc)
	325	return rc;
ca01d6dd TL	326
ca01d6dd TL	327	rc = -ENOMEM;
3a7d2fd1	328	inode = pstore_get_inode(root->d_sb);
ca01d6dd TL	329	if (!inode)
ca01d6dd TL	330	goto fail;
22a71c30 AV	331	inode->i_mode = S_IFREG \| 0444;
22a71c30 AV	332	inode->i_fop = &pstore_file_operations;
1dfff7dd	333	private = kzalloc(sizeof(*private), GFP_KERNEL);
ca01d6dd TL	334	if (!private)
ca01d6dd TL	335	goto fail_alloc;
83f70f07	336	private->record = record;
ca01d6dd	337
1edd1aa3	338	switch (record->type) {
ca01d6dd	339	case PSTORE_TYPE_DMESG:
d3762358	340	scnprintf(name, sizeof(name), "dmesg-%s-%llu%s",
1edd1aa3 KC	341	record->psi->name, record->id,
1edd1aa3 KC	342	record->compressed ? ".enc.z" : "");
ca01d6dd	343	break;
f29e5956	344	case PSTORE_TYPE_CONSOLE:
d3762358	345	scnprintf(name, sizeof(name), "console-%s-%llu",
1edd1aa3	346	record->psi->name, record->id);
f29e5956	347	break;
060287b8	348	case PSTORE_TYPE_FTRACE:
d3762358	349	scnprintf(name, sizeof(name), "ftrace-%s-%llu",
1edd1aa3	350	record->psi->name, record->id);
060287b8	351	break;
ca01d6dd	352	case PSTORE_TYPE_MCE:
d3762358	353	scnprintf(name, sizeof(name), "mce-%s-%llu",
1edd1aa3	354	record->psi->name, record->id);
ca01d6dd	355	break;
69020eea	356	case PSTORE_TYPE_PPC_RTAS:
d3762358	357	scnprintf(name, sizeof(name), "rtas-%s-%llu",
1edd1aa3	358	record->psi->name, record->id);
69020eea	359	break;
f33f748c	360	case PSTORE_TYPE_PPC_OF:
d3762358	361	scnprintf(name, sizeof(name), "powerpc-ofw-%s-%llu",
1edd1aa3	362	record->psi->name, record->id);
f33f748c	363	break;
a5e4797b	364	case PSTORE_TYPE_PPC_COMMON:
d3762358	365	scnprintf(name, sizeof(name), "powerpc-common-%s-%llu",
1edd1aa3	366	record->psi->name, record->id);
a5e4797b	367	break;
9d5438f4	368	case PSTORE_TYPE_PMSG:
d3762358	369	scnprintf(name, sizeof(name), "pmsg-%s-%llu",
1edd1aa3	370	record->psi->name, record->id);
9d5438f4	371	break;
ae011d2e	372	case PSTORE_TYPE_PPC_OPAL:
d3762358	373	scnprintf(name, sizeof(name), "powerpc-opal-%s-%llu",
1edd1aa3	374	record->psi->name, record->id);
ae011d2e	375	break;
ca01d6dd	376	case PSTORE_TYPE_UNKNOWN:
d3762358	377	scnprintf(name, sizeof(name), "unknown-%s-%llu",
1edd1aa3	378	record->psi->name, record->id);
ca01d6dd TL	379	break;
ca01d6dd TL	380	default:
d3762358	381	scnprintf(name, sizeof(name), "type%d-%s-%llu",
1edd1aa3	382	record->type, record->psi->name, record->id);
ca01d6dd TL	383	break;
	384	}
	385
ca01d6dd	386	dentry = d_alloc_name(root, name);
c39524e6	387	if (!dentry)
3a7d2fd1	388	goto fail_private;
ca01d6dd	389
83f70f07	390	inode->i_size = private->total_size = size;
ca01d6dd TL	391
	392	inode->i_private = private;
	393
1edd1aa3 KC	394	if (record->time.tv_sec)
1edd1aa3 KC	395	inode->i_mtime = inode->i_ctime = record->time;
ca01d6dd	396
fbe0aa1f	397	d_add(dentry, inode);
ca01d6dd	398
6dda9266 TL	399	spin_lock_irqsave(&allpstore_lock, flags);
	400	list_add(&private->list, &allpstore);
	401	spin_unlock_irqrestore(&allpstore_lock, flags);
	402
fbe0aa1f	403	return 0;
ca01d6dd	404
3a7d2fd1	405	fail_private:
1dfff7dd	406	free_pstore_private(private);
ca01d6dd TL	407	fail_alloc:
	408	iput(inode);
	409
	410	fail:
	411	return rc;
	412	}
	413
3a7d2fd1 KC	414	/*
	415	* Read all the records from the persistent store. Create
	416	* files in our filesystem. Don't warn about -EEXIST errors
	417	* when we are re-scanning the backing store looking to add new
	418	* error records.
	419	*/
	420	void pstore_get_records(int quiet)
	421	{
	422	struct pstore_info *psi = psinfo;
	423	struct dentry *root;
	424
	425	if (!psi \|\| !pstore_sb)
	426	return;
	427
	428	root = pstore_sb->s_root;
	429
	430	inode_lock(d_inode(root));
	431	pstore_get_backend_records(psi, root, quiet);
	432	inode_unlock(d_inode(root));
	433	}
	434
364ed2f4	435	static int pstore_fill_super(struct super_block sb, void data, int silent)
ca01d6dd	436	{
318ceed0	437	struct inode *inode;
ca01d6dd	438
ca01d6dd TL	439	pstore_sb = sb;
	440
	441	sb->s_maxbytes = MAX_LFS_FILESIZE;
09cbfeaf KS	442	sb->s_blocksize = PAGE_SIZE;
09cbfeaf KS	443	sb->s_blocksize_bits = PAGE_SHIFT;
ca01d6dd TL	444	sb->s_magic = PSTOREFS_MAGIC;
	445	sb->s_op = &pstore_ops;
	446	sb->s_time_gran = 1;
	447
366f7e7a TL	448	parse_options(data);
366f7e7a TL	449
22a71c30	450	inode = pstore_get_inode(sb);
318ceed0	451	if (inode) {
d7caa336	452	inode->i_mode = S_IFDIR \| 0750;
318ceed0	453	inode->i_op = &pstore_dir_inode_operations;
22a71c30 AV	454	inode->i_fop = &simple_dir_operations;
22a71c30 AV	455	inc_nlink(inode);
ca01d6dd	456	}
318ceed0 AV	457	sb->s_root = d_make_root(inode);
	458	if (!sb->s_root)
	459	return -ENOMEM;
ca01d6dd	460
6dda9266	461	pstore_get_records(0);
ca01d6dd TL	462
ca01d6dd TL	463	return 0;
ca01d6dd TL	464	}
ca01d6dd TL	465
fbe0aa1f TL	466	static struct dentry pstore_mount(struct file_system_type fs_type,
fbe0aa1f TL	467	int flags, const char dev_name, void data)
ca01d6dd	468	{
fbe0aa1f	469	return mount_single(fs_type, flags, data, pstore_fill_super);
ca01d6dd TL	470	}
	471
	472	static void pstore_kill_sb(struct super_block *sb)
	473	{
	474	kill_litter_super(sb);
	475	pstore_sb = NULL;
ca01d6dd TL	476	}
	477
	478	static struct file_system_type pstore_fs_type = {
ee1d2674	479	.owner = THIS_MODULE,
ca01d6dd	480	.name = "pstore",
fbe0aa1f	481	.mount = pstore_mount,
ca01d6dd TL	482	.kill_sb = pstore_kill_sb,
	483	};
	484
	485	static int __init init_pstore_fs(void)
	486	{
f9bb4882	487	int err;
fb0af3f2 JB	488
fb0af3f2 JB	489	/* Create a convenient mount point for people to access pstore */
f9bb4882 EB	490	err = sysfs_create_mount_point(fs_kobj, "pstore");
f9bb4882 EB	491	if (err)
fb0af3f2	492	goto out;
fb0af3f2 JB	493
	494	err = register_filesystem(&pstore_fs_type);
	495	if (err < 0)
f9bb4882	496	sysfs_remove_mount_point(fs_kobj, "pstore");
fb0af3f2 JB	497
	498	out:
	499	return err;
ca01d6dd TL	500	}
	501	module_init(init_pstore_fs)
	502
ee1d2674 GT	503	static void __exit exit_pstore_fs(void)
	504	{
	505	unregister_filesystem(&pstore_fs_type);
	506	sysfs_remove_mount_point(fs_kobj, "pstore");
	507	}
	508	module_exit(exit_pstore_fs)
	509
ca01d6dd TL	510	MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
ca01d6dd TL	511	MODULE_LICENSE("GPL");